Stop control means for core wrapping machines



Dec. 13,1938. J. J. KEYES STOP CONTROL MEANS FOR CORE WRAPPING MACHINES Filed Nov. 5, 1935 5 Sheets-Sheet l v lNVENTOR j obn f A eye I WITNESSES:

ATTORNEY Dec. 13, 1938. J. J. KEYES v 2, 3

I STOP CONTROL MEANS FOR CORE WRAPPING MACHINES Filed Nov. 5, 1935 3 Sheets-Sheet 2 INVENTOR .fo/7/7 f. A eyes.

BY fwf. WW

ATTORNEY J. J. KEYES 2,140,361 STOP CONTROL MEANS FOR CORE WRAPPING MACHINES Dec. 13, 1938.

. Filed Nov. 5, 1935 3 Sheets-Sheet 5 INVENTOR fa/70f fi e /es.

ATTORNEY 8w 3 5 PH/Z 4 4 a 2 2 a WW2 w W f 1 1\.\. n 4/ v VJ i M .e Z n 6 6 7 w 4 M I 7 AUG WITNESSES:

Patented Dec. 13, 1938 UNlTED STATES PATENT OFFICE STOP CONTROL MEANS FOR CORE WRAPPING MACHINES vania Application November 5, 1935, Serial No. 48,329

2 Claims.

My invention relates, generally, to wrapping machines and, more particularly, to wrapping machines which may be utilized to wrap covering materials around electrical conductors.

Wrapping heads of conductor-wrapping machines are designed to operate at comparatively high speeds. During such operation the tape is supplied to the conductor from a spool of wrapping material mounted concentric of the head and the conductor being wrapped. The spool, to be able to supply wrapping material to the conductor, is, therefore, so mounted that it may rotate with reference to the fiyer support. In operation the spool will have for conventional operation, a speed always somewhat greater than the flyer. The speed differential will depend on the size of the spool, namely, the quantity of paper or other wrapping material on the spool.

To prevent a too free relative movement between the fiyer and the spool, the spool is frictionally restrained. However, when the motor driving the fiyer is stopped, the kinetic energy of rotation always causes quantities of wrapping material to unwind from the spool. If the triotional force restraining relative movement between the flyer and spool is sufficiently increased to prevent unwrapping of the conductor covering material, then the tension in the material is far too great for normal operation of the machine.

The wastage of material and trouble of unraveling and removing the unwound material is great enough even during normal stopping of the machine, but when the tape breaks an immediate need to stop both flyer and spool arises. If the attendant does not immediately notice the break in the wrapping material, not only is wrapping material wasted but a considerable length of wire may pass through the wrapping head to the takeup reel without having been supplied with an insulating covering.

One object of my invention is to provide for adequate stopping of the spool of insulation with reference to the wrapping head of a conducetorwrapping machine.

Another object of my invention is to stop the rotation of the spool carrying insulating material in response to a break in wrapping material.

A further object of my invention is to prevent relative movement of the spool carrying material to be wrapped on a core with reference to its support in response to a stopping of the application of the material to the core.

A still further object of my invention is to prevent rotation of a member relative to another member of a pair of relatively rotatable mem- (Cl. zoo-52) bers when one of said members is decreasing in speed during the stopping thereof.

Other objects and advantages of my invention will become more apparent from a study of the following specification when taken in conjunction with the accompanying drawings, in which:

Figure l is a front elevational view of a corewrapping machine embodying the features of my invention; 7

Fig. 2 is an enlarged perspective View 'of the wrapping head of the wrapping machine, and illustrates how the wrapping material coacts with a switch element for controlling the operation of the motor driving the wrapping head, and for controlling the operation of electromagnetic braking means adapted to prevent relative movement of the spool of insulation and the base or support for the spool;

Fig. 3 shows a circuit diagram illustrating the electrical features of my invention;

Fig. 4 shows a modified circuit diagram illustrating alternative electrical features of my invention;

Fig. 5 is a side elevational view of a portion of one of the flyer posts used with my invention;

Fig. 6 is a plan view of the subject matter shown in Fig. 5 and also shows partially in section, a plan view of the binding posts used to supply the electromagnetic braking means with electric energy; and

Fig. 7 is an enlarged vertical sectional view of the liver and support for the spool carrying the wrapping material for the core to be wrapped.

Although my invention is capable of other applications than hereinafter discussed, it is particularly useful for applying a coating of narrow strips of material on a core member.

Referring now to the drawings and particularly Fig. 1 thereof, the reference character I designates, generally a panel and 2 a base upon which the various parts of my machine may be mounted. As shown, the supply reel 3 and the take-up reel i are each rotatably mounted upon transversely disposed shafts which are mounted upon the base portion 2. The remaining parts which constitute my wrapping machine, are mounted on the panel I.

In order to provide for drawing the core 5 from the supply reel 3 and bringing it into cooperative relation with a wrapping head 6, whereby the covering material may be wrapped h'elically around the core, a capstan l driven by a constant-speed motor, or in some instances a variable-speed motor, 8, is provided. As shown, the motor likewise drives the wrapping head 6 and the take-up reel 4. The capstan '1 comprises a pulley having preferably a V-shaped circumferential groove around which the moving core is wrapped one or more times in order to insure suiiicient frictional engagement to withdraw the core from the supply reel 3.

A gear unit 9 is provided for the purpose of varying the speed at which the core may be drawn through the wrapping head in relation to the speed of rotation of the latter, thereby varying the helical angle at which the material is being wrapped around the core. The gear unit is disposed to receive a plurality of sets of gear wheels (not shown), whereby the gear ratio may be changed to accommodate any desired operating condition.

As will be readily observed, for the purpose of insuring good results in wrapping the material upon the core, it is necessary to maintain the core under slight tension as it is being wrapped. To accomplish this end I provide a friction brake I comprising a pivotally mounted lever I I, a spring I2 surrounding a screw stud I3 and located beneath the free end of the lever and resting upon the nut I4 and adjustably mounted on the screw stud I3. As shown, the frictional engagement may be varied to effect any desired core tension by adjusting the tension of the spring I2 by turning the threaded nut I4.

In view of the fact that the take-up reel 4 must be driven at a higher speed when the reel is empty than when the reel is full, a frictional drive I5 which may comprise a plurality of frictional plates is utilized. Inasmuch as the take-up reel must be driven at a lower speed than the speed at which the motor normally operates, a gear reduction unit it is provided.

The wrapping head 6, in which the greater portion of my invention resides, comprises, generally, means for feeding wrapping material to the core and means for wrapping a covering material upon the core coacting with means for stopping the operation of the motor driving the wrapping head and means for preventing relative rotation of the spool 2I and the base plate 25 of the wrapping head 6 when a break occurs in the material 50 to be wrapped on the core.

In the wrapping head 6, the reference character ii designates, generally, a casing in which is rotatably mounted a spindle I8 having a longitudinal opening through which the core passes. The spindle may be driven at a high speed by a motor 8 through gears I9 and 20. The lower portion of the spindle is rotatably mounted in the casing II by anti-friction ball-bearings. The middle portion of the spindle is designed to carry a supply of material which is wound on a spool 2!, while the upper portion is adapted to drive a serving device 22 which serves to wrap the material around the core. The shank 23 of the serving device may be detachably connected to the upper end of the spindle by any suitable means, such, for example, a coupling 24 having interfitting parts.

In view of the fact that the face plate or base 25 is driven at very high speed, it is provided with a suitable depending separate flange portion, not shown, whereby it may be securely, yet rotatably, mounted in the casing II.

The spool 2i upon which the supply of material is wound, must also rotate at a high speed, namely, a speed equal to the speed at which the face plate 25 rotates, plus a speed determined by the speed at which the material is being wit-hdrawn from the spool 2E. The spool is therefore so mounted and the base thereof so constructed as to provide frictionally restrained relative rotation between the face plate and the spool. The face plate is similarly provided with friction surfaces to coact with the friction surfaces on the spool support.

The face plate 25 is rigidly secured to the spindle I8 as shown at the bottom of Fig. 7 and rotates in suitable ball bearings (not shown).

Referring to Fig. '7, the spool 2I is mounted in fixed relation to the spool support I00, having the supporting sleeve I03, which sleeve is disposed to rotate freely on ball bearings IOI and I02. The races for the ball bearings are mounted on a sleeve I 04 having vertically slidable movement on the spindle I8 in the guideways I05. A portion of the weight of the sleeve I04 is supported by spring I06.

As generally hereinbefore pointed out, the spool support I00 is restrained in its rotation relative to face plate 25 by friction rings. These rings comprise a graphite or similar ring I01 having a low coefficient of friction and a fibre ring I09 having a higher coefficient of friction. These two rings I 07 and 'I09 coact with the friction surface I08. A spring I I0 is disposed between the rings I01 and I09 with the result that they tend to be moved out of a common plane.

The friction rings I0! and I09 coact with the friction surface I08 to restrain relative rotation between the spool support I00 and the face plate 25, however, the operation is not just such a simple effect. For a heavy or full spool of insulation the springs I06 and H0 coact in such a manner that friction ring I0! is moved vertically downward by an amount sufficient to cause coaction between ring I09 and surface I08. In other words, a full spool will be restrained by a larger friction force than a nearly empty spool.

A full spool naturally has the covering material removed therefrom at a much greater distance from its center. The moment arm is much greater. If the frictional restraining force is increased proportional to a function of the spool diameter, by a proper spring adjustment and otherwise proper design, the tension in the covering material may be kept substantially constant regardless of the size or weight of the spool.

While springs I06 and H0 do coact, spring I08 is primarily used to compensate for the weight of sleeves I03 and I04 and spool support I00. The tension in the covering material can be effectively controlled by the proper adjustment of spring I I0 or by a proper selection of the size or spring effect, of the spring I I0 alone, provided the total weight variation of spool 2|, and elements I00, I03 and I04, have the proper value in relation to spring H0 and the differential effect of the friction rings I01 and I09.

Since spring IIO produces a differential movement between surfaces I01 and I09, the frictional force between spool support I00 and face plate 25 can be made a function of the moment arm of the force withdrawing the core covering, that is, the frictional force is made a function of the radius of the spool with the result that the tension with which the material, or covering, is applied remains substantially constant, thus improving the final product, Applying the material at constant tension eliminates frequent breaks of the material and the consequent need for frequent stops of the machine.

If the face plate 25 is' stopped for any reason, the spool 2|, being mounted on sleeve I03, will spin and thus tangle a considerable quantity of wrapping material. The frictional force at surface I08 and friction rings I61 and I69 is not sufficient to prevent this. As a matter of the fact the strength of the wrapping material near the desirable tension with which it is applied does not permit of such magnitude of frictional force.

To prevent tangling of the wrapping material when face plate 25 is stopped, an electro-magnetic coil 44 is mounted below spool support I00. This coil is so interconnected with a source of electric energy, preferably of low voltage, that it becomes energized when the face plate 25 is retarded, or decelerated, during stopping of the machine, that is, during open circuiting of the energizing circuit of motor 8.

With the machines at present in use, that is, machines of the prior art frequent stops are necessary during the unwrapping of a single spool to adjust the tension of the material. With my devices the frictional force between the face plate 25 and the spool support I08 is automatically varied so that the tension in the wrapping material remains substantially constant during the complete unwinding of a spool.

Another important feature of my invention is to energize the coil 44 and stop the motor, preferably through a relay, when there is a break in the covering material. During operation the covering material 56 passes from spool 2I around fiyer post II2, then under the guide. bar N3, of flyer post II4 over the guide bar H5, and under the relatively light weight V-shaped, or U-shaped switch wire II6 to the guide on the coupling 24 and the serving device 22. v

The switch H6 is loosely mounted in its bearing H1 and is so positioned with reference to the center of rotation that the centrifugal force by reason of its own weight, though small, keeps it in the bearing. Further, it is also so positioned that a small centrifugal force in. addition to its own weight tends to move it to the position shown in Figs. 5, 6 and '7.

The particular arrangement is, however, not of prime importance. It is important that no amount of slack in material 56 will cause the movement of the switch I I6 to the position shown in Figs. 5, 6 and 7, but that such movement does take place when the material breaks.

F'lyer post H4 is hollow and carries the guide bars H3 and H5 and the V-shaped switch H6. The switch I IBthrough its bearing I I1 is grounded to the machine. An electric conductor H8 is passed up through the hollow portion of the fiyer post and presents, at its upper end, a contact point 53. The circuit arrangement is such that coil 44 is energized to firmly hold the spool 2i through its support ID!) to the face plate 25 whenever a break occurs in the material 56.

Figs. 3 and 4 show two different circuit arrangements that may be used to accomplish the novel results of my invention. The circuit diagram shown in Fig. 3 requires but one slip ring 41 on the face plate Whereas the circuit diagram shown in Fig, 4 requires two slip rings 4! and 41 on the face plate 25. The arrangement shown in Fig. 4, though somewhat more expensive, has the additional advantage that no material is tangled, regardless of whether the stopping of the motor 8 is effected by reason of a break in the material or whether the stopping of the motor is effected by reason of a delibrate operation. of a stopping switch.

A better understanding of the novel operation can probably be had from a study of typical cycles of operation for the motor 8 when a break occurs in the material or when a stop switch is operated.

Assuming that switches 36 and 38 are closed, then the generator 31 is connected to conductors 26 and 32 energizing these conductors. Conductor 26 is grounded to the machine whereby the bearing is connected to the left hand terminal of the source of energythe generator 31.

To start the motor 8, after the material has been threaded on the guides and core, the attendant operates switch 21, thereby establishing a circuit from grounded conductor 26 through switch 21, actuating coil 28 of the motor contactor 29, conductor 36, and back contact members 3I of control contactor 49 to the energized conductor 32. Motor contactor 29 establishes its own holding circuit through contact members 33 and also closes contact members 34.

Closing of contact members 34 establishes an energizing circuit for the motor 8. This circuit may be traced from grounded conductor 26, through contact members 34, motor 8, and back contact members 35 to conductor 32.

When a break occurs in the material, V-shaped switch II6 drops on the contact point 53 thereby establishing an energizing circuit from grounded conductor 26, through bearing 52, V-shaped switch II6, contact point 53, connector 43, coil 44, connector 45, conductor 46, slip-ring 41, and actuating coil 48 of the control contactor 49 to the conductor 32.

Since coil 44 is energized, a magnetic clutch effect is established between spool support I60 and face plate 25 with the result that no further relative rotation takes place, Simultaneously with the operation or energization of coil 44, contact members 3| and 35 are opened. Opening of contact members 35 stops motor 8, whereas opening of contact members 3| resets the starting circuit so that pushbutton switch 21 must be operated before motor 8 can be started. The motor 8 could thus not be started by merely lifting the V-shaped switch II6 during re-threading of the machine.

It will be noted that the stop switch 40, slipring 4| and conductor 42 merely constitute a shunt for the circuit through switch I I6. Operation of the stop switch 40 thus eifects the stopping of motor 8 and the braking of the spindle in exactly the manner accomplished by a break in the material which closes switch 56.

The circuit arrangement shown in Fig. 3 is somewhat simpler and cheaper and is the circuit arrangement actually used with the apparatus built in accordance with the showing in Figs. 5, 6 and 7. A break in the material grounds contact point 53, thereby establishing a circuit from the grounded conductor 26 through bearing 52, switch II6, contact point 53, coil 44, slip-ring 41, coil 48 of control contactor 49, switch 36, generator 31 and switch 36, back to grounded conductor 26.

Operation of control contactor 49 opens the contact members 35 and thus stops the motor substantially simultaneously with the energization of the coil 44.

The nut 2I3 is screw threaded on spindle I8 and when screwed down against the sleeve I64 nullifies the cooperative action of springs I66, I I0 and friction means I01, I68, and I09. Occasion may arise for the use of nut 2I3 by reason of the nature of the covering and the character of the covered core desired, but ordinarily nut 2I3 is not needed and in fact constitutes no part of my invention. The nut 2 I3 is merely shown to illustrate the actual structure of a machine embodying the features of my invention.

Although I have shown and described certain specific embodiments of my invention, I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

I claim as my invention:

1. A centrifugally operable switch, in combination, a rotatable base, a post disposed on the base and parallel to the axis of rotation of the base, a contact disposed substantially concentric of the post and insulated therefrom, a U-shaped member pivotally mounted on the post, the axis of the pivot being disposed in one of the legs of the U, being disposed between the contact on the post and the axis of rotation of the base in a plane, including the contact, perpendicular to the axis of rotation of the base, and being substantially perpendicular to a line, falling in the said plane,

joining the contact and the axis of rotation of the base, whereby rotation of the base and thus the revolutions of the post about the axis of rotation of the base will cause centrifugal forces to act on the U-shaped member to make electrical engagement with the free leg of the U and the contact, and, means for normally holding the free leg of the U out of engagement with the contact.

2. A centrifugal operable switch as described in combination, a support adapted to revolve about a fixed axis, a contact member mounted on said support and insulated therefrom, a U- shaped member pivotally mounted on the support, said U-shaped member being mounted to pivot on one of its legs and so disposed that the other leg may make electrical contact with said contact member, and means for normally holding the leg of the U disposed to make electrical contact with said contact member out of contact with the contact member.

JOHN J. KEYES. 

